It measures the leakage current and uses that measurement to see what *change* of collector current has occurred as a result of it applying some base current. The DCA55 does take into account leakage current when measuring gain. Of course, gain can vary at different test conditions, so that can explain why measurements from one piece of test gear to another can be different.Ģ. It is common for many other gain testers to measure at different currents, some don't even specify the collector test current (I know my multimeter doesn't specify the test current at all). For example, the DCA55 measures gain for a collector test current of nominally 2.5mA and a collector voltage of around 2-3V. The DCA55 booklet is fairly detailed and shows the test conditions used for measuring gain. I'll try and cover some of the points made, forgive me if I miss anything.ġ. I appreciate the points made by the OP and also the replies. Jez Siddons from Peak Electronic Design Ltd here, the designer and maker of the DCA55.Īpologies for the delay in replying to this post, I've only just found it, otherwise I would have replied a long time ago.
Out of all these, I have no idea which is the most accurate.and I'm not sure how the Peak accounts for leakage. It could go either way by approx 5% - 15% The gains were pretty close to using R.G.'s method. The Peak is much more accurate identifying germanium.Very few failures. 128įor lower gain ones, the Metex is still the lowest, but Peak and R.G.
It's approx 10% higher than the Metex and R.G. Regarding measures in between my Metex 3800 and R.G.'s method for medium gain transistors. For the last 30 minutes I went through a bunch (with hFe 15+) and the DCA55 reported mainly "darlington", some "common diode network", a few "digital transistor", and one "germanium". I just purchased it to analyze a bunch of vintage metal can silicons & germs, and the massive FAIL was with PNP silicon. It's sad.After all the glowing reviews & recommendations, and a cost of $60-$70, I really expected better.
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